Method for judging and processing floating coke in dry quenching chute area

Abstract

According to the method, reasons for forming coke floating in the coke dry quenching chute are analyzed, rapid judgment and efficient treatment are taken as main purposes, on the premise of ensuring the safety of the system, the severity of coke floating is judged in advance through process parameters such as system pressure, coke discharging temperature and one-time dust removal and ash patting conditions, and then a corresponding treatment mode is selected; the floating coke is quickly and efficiently treated by cooperatively adjusting parameters such as circulating air volume, coke discharge amount, air introduction amount, desulfurization valve opening degree and insertion depth of a material blocking rod. Compared with a previous processing method, the method has great advantages in the aspects of processing speed and safety, and the purposes of fine control and safe operation are achieved.

Description

Technical Field

[0001] The invention relates to the field of metallurgical coking, and in particular to a method for determining and processing floating coke in a dry coke chute area. Background Art

[0002] Coke dry quenching is a coke quenching process that uses direct contact heat exchange between hot coke and inert gas. The pre-storage chamber of the dry quenching furnace is located at the top of the furnace. Its main function is to store red coke and continuously supply the heat of red coke to the cooling chamber, reducing the time interval between coke loading and the fluctuation of circulating gas temperature, and continuously supplying heat to the boiler, thereby ensuring the stability of steam parameters.

[0003] In the CDQ production, the circulating air volume needs to match the coke discharge volume. The circulating air volume needs to increase with the increase of the coke discharge volume, and the increase of the circulating air volume each time needs to be controlled within a given range. If it exceeds the range, the airflow will pass through the cooling section of the CDQ furnace, causing it to flow into the annular flue through the ramp, thereby blowing up the coke in the ramp. After the coke is blown up, space will be formed to allow the surrounding coke to complete the filling, which will cause the coke to accumulate at the ramp and cause the coke surface to rise.

[0004] During the normal operation of CDQ, the boiler inlet pressure, pre-storage section pressure, and circulating air volume are relatively stable. The relevant parameters of the CDQ system are stable, and the general air-to-material ratio is 1250-1350 m3 / t. When the air-to-material ratio exceeds the limit value, or the circulating air volume increases too much, when the circulating gas enters the annular flue through the chute, a part of the coke will be blown up at the chute, causing the coke to accumulate too high at the chute, and the coke surface rises, that is, the coke floats. After the coke floats, medium and small coke blocks will flow to the primary dust collector, causing the primary dust collector ash discharge system to be blocked. A large amount of coke powder in the primary dust collector will be brought into the boiler system by the circulating gas, reducing the life of the boiler furnace tube and reducing the production capacity of the CDQ system. It will also increase the boiler inlet temperature and increase the concentration of combustible gas components in the circulating gas, causing system safety hazards.

[0005] Originally, when the coke floated at the chute, the CDQ furnace would stop loading coke and quickly reduce the circulating air volume. However, this method had many defects when applied. First, it took a long time. It took 8 hours from the beginning of the treatment to full recovery, which reduced the operating efficiency of the CDQ rate. Second, the boiler would be decoupled due to the decrease in steam temperature and pressure, and could not produce normally, which in turn affected the economic benefits. Third, when the system temperature of the CDQ furnace changes drastically, the refractory material of the furnace body will be damaged. Fourth, when the temperature and pressure parameters in the system are unbalanced, the operating risk of the entire circulation system will increase.

[0006] By inventing a method for determining and processing floating coke in the chute area and combining a variety of adjustment means, the generation of floating coke in the chute area can be effectively monitored and suppressed. If floating coke occurs, it can be quickly processed through the operating means provided by the method, thus shortening the shutdown time, improving the economic benefits of dry quenching, and ensuring the safe and smooth operation of the system. Summary of the invention

[0007] The purpose of the present invention is to provide a method for determining and processing floating coke in a dry quenching chute area in view of the above problems.

[0008] The object of the present invention is achieved as follows: A method for determining floating coke in a dry coke quenching chute area, comprising the following aspects: 1) Under normal production conditions, the pre-storage section pressure in the circulating gas system is set to 0 to -100 Pa, and the boiler inlet pressure is -0.8 kPa to -1.1 kPa. When slight floating coke occurs, the boiler inlet pressure will fluctuate frequently between -0.6 kPa and -1.3 kPa. When severe floating coke occurs, the boiler inlet pressure will drop sharply to below -1.3 kPa. At this time, the pre-storage section pressure rises to a positive pressure of 100 Pa to 2000 Pa. If coke is loaded at this time, smoke and dust will overflow from the furnace mouth accompanied by an explosion sound; 2) After floating coke occurs, the circulating air volume is reduced to 30,000 to 50,000 m3 without changing the circulating fan speed. 3 / s; 3) Under normal circumstances, the discharge temperature of CDQ is controlled at 105℃~140℃. If floating coke occurs, the air volume and discharge volume do not match, that is, the air-to-material ratio is from 1250~1350m 3 / t reduced to 1000m 3 / t or less, the coke discharge temperature rises to 140℃~180℃, and red coke is discharged; 4) After floating coke occurs, the temperature of the upper part of the water-cooling jacket is between 60℃~100℃.

[0009] A method for treating floating coke in a dry quenching chute area comprises: method 1: when the coke at the inclined flue is less floated and scattered, and it is discovered in the early stage: 1) reduce the coke discharge volume to 40t / h-60t / h, reduce the speed of the circulating fan to 600rad / min-800rad / min, and wait for the coke at the inclined flue to return to its original state, that is, the state where the coke accumulation angle of repose is 130°-150°; 2) after the coke floating phenomenon disappears, slowly increase the coke processing volume to 150-200t / h and the circulating gas volume to 150000-170000m 3 / h; Method 2: When the coke in the inclined flue is completely floating: 1) Stop loading red coke into the CDQ furnace; 2) Reduce the speed of the circulating fan to 300rad / min~400rad / min, and continue to discharge coke according to the setting of the maximum coke discharge temperature of 190-230℃; 3) Adjust the pre-storage section pressure to 50Pa~-100Pa through the desulfurization valve and the air introduction valve; 4) When the coke level in the CDQ furnace drops to 300-400mm lower than the bottom of the inclined flue, stop discharging coke; 5) Confirm that all the coke blocked in the inclined flue has fallen and the floating phenomenon has disappeared; 6) Slowly increase the coke processing capacity to 80t / h~120t / h, and increase the circulating fan speed to 900rad / min~1200rad / min within 30min, and restore to the original operating conditions, that is, the coke processing capacity is 150-200t / h, and the circulating gas volume is increased to 150000-170000m 3 / h.

[0010] When operating the circulating air volume once, adjust the regulating modulus of the circulating air inverter from 1% to 0.1-0.5%. When increasing the circulating air volume, increase it gradually by 15-75rad each time.

[0011] When checking the coke floating phenomenon, attention should be paid to the phenomenon that the air is sucked into the annular air duct through the inspection hole, causing abnormal combustion and resulting in an increase in the boiler inlet gas temperature.

[0012] In the process of implementing the above methods one and two, it is necessary to control the combustible components of the circulating gas within a reasonable range by adjusting the air introduction amount, that is, O2≤1%, H2≤3%, CO≤6%.

[0013] The beneficial effect of the present invention is that it takes 6h to 8h to deal with the coke floating problem, but this method can reduce the time to 3h to 4h. According to the electricity generation of 8500KWh per hour for each dry quenching furnace and the industrial electricity consumption of 0.5 yuan / KWh, based on the treatment of 9 coke floating last year, the annual economic benefits saved = 9×3.5×8500×0.5 = 133875 yuan. This does not include the extended economic losses caused by the quality fluctuation of coke due to the ineffective suffocation in the dry quenching furnace; In addition, in the process of dealing with coke floating, the temperature of the dry quenching furnace does not undergo temperature fusion, which will not damage the refractory of the dry quenching furnace body, thereby extending the service life of the dry quenching furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be further described below in conjunction with the accompanying drawings.

[0015] Figure 1 It is a schematic diagram of the normal and floating coke states of the chute area of ​​the present invention.

[0016] Among them: 1. Floating coke, 2. Normal coke repose angle. DETAILED DESCRIPTION

[0017] 1. Concept of the scheme: 1.1 Analysis of the causes of floating coke: The 150t / h CDQ furnace of the Taigang Coking Plant has 20 evenly distributed ramps in the circumferential direction. After the circulating gas exchanges heat with the hot coke in the cooling section, it is collected into the annular flue through the ramps. The ramp area is the only circulating gas outlet of the CDQ furnace body, and its resistance loss determines the matching relationship between the air volume and the coke discharge temperature of the entire system. The floating coke phenomenon in the ramp area is the main reason for the sharp increase in resistance loss in the ramp area.

[0018] The floating coke formation process is divided into two important stages. The first stage: After the coke from the pre-storage section enters the chute area, a coke pile with a certain repose angle is formed. When the circulating cooling gas volume and flow rate do not change, the coke in the chute area is always in a resting state, and the CDQ furnace system operates normally. This stage is collectively referred to as the coke resting stage in the chute area. During this period, affected by the shape of the coke pile, the repose angle and the inclination angle of the chute area, the circulating gas forms a significant velocity distribution difference in the length direction of the chute area outlet. There is an obvious velocity gradient in the circulating gas at the outlet of the chute area, and the airflow velocity gradually decreases from the annular inner wall to the outside of the CDQ furnace. The maximum velocity area is in the area where the inner wall of the annular flue and the chute area intersect, and the velocity is close to 60m / s. The second stage: When the circulating gas volume increases or the coke in the CDQ furnace is severely segregated, the circulating gas velocity entering the chute area will increase sharply. Once the maximum velocity of the circulating gas in the intersection area between the inner wall of the annular flue and the chute area exceeds the critical fluidization velocity of the coke pile, the coke in this area will fluidize. At this time, the coke will be blown into the chute area, and the amount of coke flowing out of the chute area will decrease. As the coke in the chute area continues to increase, the resistance loss of the chute area increases sharply, and this is the stage of floating coke generation.

[0019] 1.2 Determination and treatment of floating coke: After floating coke occurs, the resistance in the inclined area increases sharply and the distribution of circulating air volume is extremely uneven. Therefore, the following parameters can be used to comprehensively determine whether floating coke occurs: 1) Change in circulating gas pressure at the boiler inlet; 2) Whether there are a large number of small coke blocks in the primary dust collector coke cooling pipe; 3) The year-on-year decrease in circulating air volume; 4) The fluctuation range of coke discharge temperature. When the occurrence of floating coke is confirmed, normal production can be quickly restored by comprehensively adjusting parameters such as circulating air volume, dry quenching furnace material level, coke discharge volume, boiler load, etc. according to the cause of the occurrence.

[0020] 2. Specific plan: 2.1 Judgment method: 1) Under normal production conditions, the pre-storage section pressure in the circulating gas system is set to 0~-100Pa, the boiler inlet pressure is -0.8kPa~-1.1kPa, and the pressure is relatively stable when the CDQ furnace is loaded with coke. When there is slight coke floating, the boiler inlet pressure will fluctuate frequently between -0.6kPa~-1.3kPa; when there is severe coke floating, the boiler inlet pressure will drop sharply to below -1.3kPa, and the pre-storage section pressure will rise to positive pressure (100Pa~2000Pa). If coke is loaded at this time, smoke and dust will overflow from the furnace mouth accompanied by explosions.

[0021] 2) When floating coke occurs, the circulating gas resistance increases. Under the condition that the circulating fan speed remains unchanged, the circulating air volume will decrease by 30,000 to 50,000 m 3 / s.

[0022] 3) Under normal circumstances, the discharge temperature of CDQ is controlled at 105℃~140℃. If floating coke occurs, the circulation air volume will decrease accordingly as the resistance of the circulating gas system increases. At this time, the air volume does not match the discharge volume (the air-to-material ratio is from 1250~1350m 3 / t reduced to 1000m 3 / t or less), the red coke cannot be fully cooled, causing the coke discharge temperature to rise to 140℃~180℃, and even red coke is discharged.

[0023] 4) After floating coke occurs, coke with smaller particle size and lighter weight will enter the primary dust collector from the ramp along with the circulating gas and be discharged from the format valve, and may even block the format valve. This phenomenon can be manifested by on-site dust removal and the temperature of the upper part of the water-cooling jacket (under normal circumstances, the temperature of the upper part of the water-cooling jacket is between 130℃ and 220℃, and when dust removal is not smooth, the temperature is between 60℃ and 100℃).

[0024] 2.2 Treatment methods: Method 1: When the coke floating and scattering at the inclined flue are less and discovered at an early stage. 1) Reduce the coke discharge volume to 40t / h~60t / h, reduce the circulating fan speed to 600rad / min~800rad / min, and wait for the coke at the inclined flue to return to its original state. 2) After the coke floating phenomenon disappears, slowly increase the coke processing volume and circulating gas volume to return to the original operating conditions.

[0025] Method 2: The coke in the inclined flue is in a completely floating state: 1) Stop loading red coke into the CDQ furnace. 2) Reduce the speed of the circulating fan to 300rad / min~400rad / min, and continue to discharge coke according to the setting of the maximum coke discharge temperature not exceeding 230℃ (water equivalent method) to reduce the coke level in the CDQ furnace. 3) At this time, adjust the pre-storage section pressure to 50Pa~-100Pa through the desulfurization valve and the air introduction valve. 4) When the coke level in the CDQ furnace drops to 300mm lower than the bottom of the inclined flue, stop discharging coke. The coke will be affected by friction and its own gravity, which will further improve the problem of coke floating. 5) Confirm that the coke blocked in the inclined flue has fallen and the floating phenomenon has disappeared. 6) Slowly increase the coke processing capacity to 80t / h~120t / h, increase the circulating fan speed to 900rad / min~1200rad / min within 30min, and return to the original operating conditions.

[0026] Note: If the coke floats, the above treatment method should be taken as the first priority. 2) When operating the primary circulation air volume, adjust the adjustment modulus of the circulation air inverter from 1% to 0.1% to prevent the air volume from changing too much and causing adverse effects on the system. 3) When opening the inspection hole cover above the inclined flue to check the coke float, special attention should be paid to the phenomenon that the air is sucked into the annular airway through the inspection hole, resulting in abnormal combustion and the rise of the boiler inlet gas temperature. 4) In order to avoid the coke float at the inclined flue, the circulation gas volume should be increased in small amounts and gradually. Especially when the gas volume is close to the coke float phenomenon, it should be operated more carefully. 5) In the process of implementing the above method, it is necessary to control the combustible components of the circulation gas within a reasonable range (O2≤1%; H2≤3%; CO≤6%) by adjusting the air introduction volume. 5) The reasons for the coke float phenomenon may be the following, and care should be taken to prevent it from happening again.

[0027] The amount of circulating gas increases too quickly. The falling speed and particle size distribution of coke in the CDQ furnace change for some reason, resulting in uneven airflow distribution in the circumferential direction of the CDQ furnace.

[0028] It is used in 4 sets of CDQ in Taigang Coking Plant. After use, the judgment and treatment of coke floating phenomenon in the inclined area of ​​the CDQ furnace are faster and more efficient, and the time for restoring normal production rhythm is greatly shortened, playing a huge role in protecting the safe operation of CDQ furnace equipment and systems. Example 1

[0029] There is less coke floating and scattering at the inclined flue of Taigang No. 1 CDQ furnace, which is an early discovery: 1) Reduce the coke discharge volume to 50t / h, reduce the circulating fan speed to 700rad / min, and wait for the coke at the inclined flue to return to its original state, that is, the coke accumulation repose angle is 130°-150°; 2) After the coke floating phenomenon disappears, slowly increase the coke processing volume to 160t / h and the circulating gas volume to 150000m 3 / h; normal operation later. Example 2

[0030] In the early stage of Taigang No. 3 dry quenching furnace, no coke floating and scattering were found at the inclined flue of No. 3 dry quenching furnace. In the later stage, when the coke at the inclined flue of No. 3 dry quenching furnace was in a completely floating state: 1) Stop loading red coke into the dry quenching furnace; 2) Reduce the speed of the circulating fan to 350rad / min, and continue to discharge coke according to the setting of the maximum coke discharge temperature of 195℃; 3) Adjust the pre-storage section pressure to 50Pa through the desulfurization valve and the air introduction valve; 4) When the coke level in the dry quenching furnace drops to 300mm lower than the bottom of the inclined flue, stop discharging coke; 5) Confirm that all the coke blocked in the inclined flue has fallen and the floating phenomenon has disappeared; 6) Slowly increase the coke processing capacity to 100t / h, and increase the circulating fan speed to 1000rad / min within 30min to restore to the original operating conditions, that is, the coke processing capacity is 160t / h, and the circulating gas volume is increased to 150000m 3 / h, and then run normally.

[0031] Through the boiler inlet, pre-storage chamber pressure, coke discharge temperature, and primary dust removal and ash discharge conditions, the severity of coke floating is first determined, and then different treatment methods are adopted; before adjusting the air volume, the adjustment modulus in the circulating air inverter is adjusted from 1% to 0.1% to prevent excessive changes in air volume from causing adverse effects on the system; due to the large adjustment parameter range, the pre-storage chamber pressure can be appropriately maintained at a slightly positive pressure during the treatment process.

[0032] The above description is only a specific embodiment of the present invention, but the structural features of the protection scope of the present invention are not limited thereto. Any changes or modifications made by any technician in the field of the present invention are all covered by the patent scope of the present invention.

Claims

1. A method for determining floating coke in a dry quenching chute area, characterized by: These include: 1) Under normal production conditions, the pre-storage section pressure in the circulating gas system is set to 0~-100Pa, and the boiler inlet pressure is -0.8kPa~-1.1kPa. When slight coke floating occurs, the boiler inlet pressure will fluctuate frequently between -0.6kPa~-1.3kPa. When severe coke floating occurs, the boiler inlet pressure will drop sharply to below -1.3kPa. At this time, the pre-storage section pressure rises to a positive pressure of 100Pa~2000Pa. If coke is loaded at this time, smoke and dust will overflow from the furnace mouth accompanied by explosion sounds; 2) After floating coke occurs, the circulating air volume is reduced to 30,000-50,000m3 while the circulating fan speed remains unchanged. 3 / s; 3) Under normal circumstances, the discharge temperature of CDQ is controlled at 105℃~140℃. If floating coke occurs, the air volume and discharge volume do not match, that is, the air-to-material ratio is from 1250~1350 m 3 / t reduced to 1000m 3 / t or less, the coke discharge temperature rises to 140℃~180℃, and red coke is discharged; 4) After floating coke occurs, the temperature of the upper part of the water-cooling jacket is between 60℃ and 100℃.

2. A method for treating floating coke in a dry quenching chute area, characterized by: include: Method 1: When the coke floats and scatters less at the inclined flue, it is an early discovery: 1) Reduce the coke discharge rate to 40t / h~60t / h, reduce the circulating fan speed to 600rad / min~800rad / min, and wait for the coke at the inclined flue to return to its original state, that is, the coke accumulation repose angle is 130°-150°; 2) After the coke floating phenomenon disappears, slowly increase the coke processing capacity to 150-200t / h and the circulating gas volume to 150000-170000m 3 / h; Method 2: When the coke at the inclined flue is completely floating: 1) Stop loading red coke into the CDQ furnace; 2) Reduce the speed of the circulating fan to 300rad / min~400rad / min, and continue to discharge coke at the maximum coke discharge temperature of 190-230℃; 3) Adjust the pre-storage section pressure to 50Pa~-100Pa through the desulfurization valve and air introduction valve; 4) When the coke level in the CDQ furnace drops to 300-400mm below the bottom of the inclined flue, stop discharging coke; 5) Confirm that the coke stuck in the inclined flue has fallen down and the floating phenomenon has disappeared; 6) Slowly increase the coke processing capacity to 80t / h~120t / h, increase the circulating fan speed to 900rad / min~1200rad / min within 30min, and restore to the original operating conditions, that is, the coke processing capacity is 150-200t / h, and the circulating gas volume is increased to 150000-170000m 3 / h.

3. The method for treating floating coke in the dry quenching chute area according to claim 2, characterized in that: When operating the circulating air volume once, adjust the regulating modulus of the circulating air inverter from 1% to 0.1-0.5%. When increasing the circulating air volume, increase it gradually by 15-75rad each time.

4. The method for treating floating coke in a dry quenching chute area according to claim 2, characterized in that: When checking the coke floating phenomenon, attention should be paid to the phenomenon that the air is sucked into the annular air duct through the inspection hole, causing abnormal combustion and resulting in an increase in the boiler inlet gas temperature.

5. The method for treating floating coke in the CDQ chute area according to claim 2, characterized in that: In the process of implementing the above methods one and two, it is necessary to control the combustible components of the circulating gas within a reasonable range by adjusting the air introduction amount, that is, O2≤1%, H2≤3%, CO≤6%.

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